Concerning many of fibers used for resin reinforcement represented by carbon fibers and glass fibers (hereinafter referred to as “reinforcing fibers”), the bundle of these fibers (hereinafter referred to as “reinforcing fiber bundle”) is impregnated with matrix resin to obtain a so-called prepreg and, thereafter the same is made into a preform in a predetermined shape, thermally cured and manufactured as fiber-reinforced plastic molding.
These years, along with the weight reducing trend of such fiber-reinforced plastic molding, a high quality prepreg of thin and reduced in thickness irregularity is expected.
When producing such prepreg, it is necessary to open in a thin and wide web without twisting, in order to fully deploy the high elastic modulus property of individual single fibers composing the reinforcing fiber bundle.
Therefore, also for the reinforcing fiber bundle used as an original material of the prepreg, it has become an important subject to wind around a bobbin, beforehand, in such a thin and uniformly spread state, and, to supply to the process for producing the prepreg all the way maintaining this state.
To realize handling such a fiber bundle, especially, it is important not to apply unnecessary external force to the fiber bundle during the conveying and guiding of the fiber bundle and, for instance, regulation of the yarn path by means of a ribbed roll causes the fiber bundle friction and folding and causing troubles, which are not necessarily undesirable. Therefore, it is usual to use a wide guide roll anticipating variation of the yarn path, in other words, allowing variation of the yarn path.
However, the stabilization of the yarn path becomes an important subject, because variation of the yarn path induces deterioration in the quality of the winding package.
As the fiber bundle traveling obliquely on the guide roll also induces the friction of the fiber bundle and deterioration in the quality of the yarn, the stabilization of the yarn path is similarly an important subject.
On the other hand, in the ordinary fiber bundle winding device, the fiber bundle is traversed in the shaft direction of the bobbin by a traverse guide reciprocating parallel to the rotating shaft of the winding bobbin and wound.
In such traversing device, the stabilization of the yarn path is an important subject, variation of the yarn path disordering the winding package and deteriorating in the quality of the package.
Besides, if a fiber bundle is pulled laterally, the fiber bundle travels obliquely on the guide roll. Like this, if a fiber bundle does not travel straight in the circumferential direction of the guide roll, but travels obliquely on the guide roll, friction occurs in the fiber bundle, deteriorating in the quality of the fiber bundle.
Conventionally, as the fiber bundle winding device for winding flat tape-like reinforcing fiber bundle spread thin beforehand as mentioned above with a stable yarn width (width of fiber bundle) from the beginning to the end of winding, FIG. 2 of Japanese Patent Laid-Open No. 2001-348166 proposes a fiber bundle winding device comprising a guide stand reciprocating parallel to the rotating shaft of the winding bobbin, a pair of upper guide rollers arranged at the upper part of the guide stand with the rotating shaft thereof crossing the rotating shaft of the winding bobbin at a right angle, a pair of lower guide rollers arranged at the lower part of said guide stand with the rotating shaft thereof parallel to the rotating shaft of the winding bobbin, and a conical guide roller arranged therebetween for twining the fiber bundle by 90° in the shaft line direction.
Moreover, as winding device having an swing guide, FIG. 5 of Japanese Patent Publication No. 3194765 proposes a winding device or the like for winding a narrow-width belt-like body around a drum all the way crossing the line parallel to the winding direction of the narrow-width belt-like body and the rotating shaft line of said swinging sticking roller at a right angle, by swinging the final sticking roller for sending the narrow-width belt-like body to the winding drum with a normal line to the outer surface of the winding drum as swing center point.
However, these conventional fiber bundle winding devices had drawbacks as mentioned below.
In the fiber bundle winding device disclosed in FIG. 2 of Japanese Patent Laid-Open No. 2001-348166, one of the pair of upper guide rollers set at the upper part of the guide stand is formed into a saddle shape of which outer surface is curved inwards in the middle. As a result, this curved surface restricts the fiber bundle to prevent the yarn path deviating from the original yarn path. However, to restrict the fiber bundle by the saddle-like guide roll is to apply the force in the width direction of the tape-like fiber bundle, causing troubles such as entanglement of single fibers by the collapse of fiber bundle and, moreover, the yarn width of the wound fiber bundle becomes narrower. Moreover, in the publication, saddle-like guide roll are provided at the lower guide for limiting the side slipping of fiber bundle on the lower guide rollers due to the traversing and this also causes the collapse of fiber bundle and entanglement of single fibers, and the yarn width of the wound fiber bundle becomes narrower. Furthermore, conical or saddle-like guide roll generates peripheral speed difference in the yarn width direction, damaging the fiber bundle and deteriorating in the quality.
In addition, FIG. 5 of Japanese Patent Publication No. 3194765 discloses a guide wherein a guide extending in the supplying direction of a narrow-width belt-like body is linked to a bracket supported so as to swingable in the horizontal direction, and the bracket having a drum-like supplying roller of which central part in an axial direction bulges outward. It is described that this allows the guide to direct to the supplying direction of narrow-width belt-like body by swinging the guide in the horizontal direction and the drum-like supplying roller allows substantially centering of the narrow-width belt-like body.
However, in case of the fiber bundle, the use of drum-like roller only widens the fiber bundle width, but centering can not be expected. Moreover, the swinging of the guide directs the guide roll to the supplying direction of narrow-width belt-like body and is effective because the position of narrow-width belt-like body on said supplying roller is fixed, however, in case of the fiber bundle, the yarn path on the supplying roll is unstable, the fiber bundle deviates from the supplying roll, inhibiting the winding.
Similarly, the sticking roller which is the final guide roll is an idea of fixing the travel position of the narrow-width belt-like body using a rib, and can not be applied to the winding of fiber bundle.